Shiva Mark III
I’ve been out and about; I am back to write an update.
I’ve spent part of tonight modeling subwoofer enclosures on this great program called WinISD for the Shiva Mark III. The program has an unbelievable help file and a great graphing system. Now I just learned all this tonight, so bear with me: The idea of a ported enclosure is to increase the efficiency of the subwoofer driver; in other words, it makes it easier for the thing to move air when there is a hole in the box. Each driver reacts differently to the same box because they have unique sets of properties. This program allows the user to enter in those properties and then to run box size simulations. In the shot below I have a simulation of a closed box of 66L (4027.6 cubic inches), which is graphed in yellow. See as the frequency drops, the volume that the sub is able to produce in the box drops as well. Going from right to left, the yellow line drops off quite early. However, take a look at the green line. That’s a 100L (17.48” X 16.00” X 30.00”, 6102.4 cubic inch) box that is ported. “Ported” means it has a 4” square air “tube” that guides air out. The length of this tube is precisely calculated by the program as 22.4” (as you can see) and that is what lets the green line on the graph stay up higher. But, “that line drops off as well” you say? Not to fear, I can solder out (there are instructions, don’t worry) two resistors on the 250W plate amp that I am looking at and they will boost the green line by 4dB between 20Hz and 23 Hz, which will bring that green line nearly horizontal (albeit artificially for those last 3 Hz) down to 20 Hz, which is nearly feeling, not hearing, territory. Anyways, the box will be constructed out of MDF (haven’t determined the width) and I am waiting on more information on what to use to acoustically dampen the inside. Either way, I am pretty excited about the project - it has the potential to work. We’ll see, though. We’ll see.
Glad I got that out of my system. Anyways, philosophy presentation tomorrow. I’m going to have them light candles for a demonstration of one of Descartes’ ideas - watch out! If JRC is burning tomorrow, you’ll know it’s my fault.
Listened to some music on the Infinity’s at home: pure bliss. Near field listening is really a lot of fun; except the crossovers on those old speakers can be really noticeable - at the beginning of one of Jack Johnson’s songs, I would keep hearing his voice dip into the upper woofer from the midrange and then back to the midrange - really weird. I’m off track again - we sent the HPM-60 woofers into refoam (my I haven’t updated since I told ya’ll about picking those up) and so those will be coming back. Additionally, the turntable restoration is going well: the belt, cartridge, and stylus pressure gauge were ordered today. It looks as if we may get a dustcover as well. Finally, I am waiting to hear on a SX-838 which I could get for free; however it will be about $100 to get it in tip-top shape (a more than worthwhile investment, that’s for sure).
Life has been going quite well; the weather warmed up a little today. I am preparing for J-Term, Spring Semester, and Summer already … I like to have a plan and classes are going so well that it’s a lot of fun to prepare for the one’s coming up. Like I said before, somewhere along the way I lost my ability to worry - I certainly hope I don’t find it again for a while. I almost forgot; everyone came back this weekend. I can’t keep track of everyone that was at Steve’s house: Steve, Matt, Shayla, John, Nils, Charlie, Kim, Jimmy, Karin, Katie, Theron, Trisha, Richard, Nick, Doug, Ryan, Laura, Danielle, Katherine (happy birthday Katherine! I really really didn’t mean what I said to be an insult!! [boy I feel guilty about that one]), and even Other People. Disclaimer: if I left you out, it’s an honest mistake and not an indication of anything else. Matthew even called - he kicked butt in his performance just because he’s a freakin’ amazing singer/actor like that. Yes, someday Matthew will be richer than all of us. Steve and I had a good long talk. Saturday night me, Steve, Matt, and John watched Will Ferrell it was amazingly funny again: “Mondays, for I hate Mondays… They-ay make me so steamed! … Weekends! I prefer the weekends! uh oh oh oh oh oh!!! SONOFABITCH!” Yes it’s a hell spawned Fender. Garth Brooks and Will Ferrell as the devil, what more could you ask for.
To return to my stereo listening; “All I Ask of You: Reprise” from Phantom of the Opera:
I gave you my music
Made your soul take wing
And now, how you’ve repaid me
Denied me and betrayed me
He was bound to love you
When he heard you sing
It sounded so pure and clean, and I haven’t even gotten the DC-offset looked at on that amp. Man, I have a lot to learn. So, you made it to this part of the post? Well, it confirms your suspicions that a.) I have been really busy and b.) I am really getting into audio. Why? I don’t know, how about this: because I can. But seriously, I am getting a little punchy as it’s rather late/early. Tomorrow is homework day!
Know yourself. Judge yourself. Be yourself.